CHAPTER 6. MANAGING DATA RESOURCES

1
CHAPTER 6. MANAGING DATA RESOURCES
2
LEARNING OBJECTIVES

• COMPARE TRADITIONAL FILE ORGANIZATION
  MANAGEMENT TECHNIQUES
• EXPLAIN PROBLEMS OF TRADITIONAL FILE ENVIRONMENT
• DESCRIBE HOW DATABASE MANAGEMENT SYSTEM
  ORGANIZES INFORMATION

3
LEARNING OBJECTIVES

• IDENTIFY TYPES OF DATABASE, PRINCIPLES OF
  DATABASE DESIGN
• DISCUSS DATABASE TRENDS
• ANALYZE MANAGERIAL, ORGANIZATIONAL REQUIREMENTS
  FOR CREATING DATABASE ENVIRONMENT

4
MANAGEMENT CHALLENGES

• TRADITIONAL DATA FILE ENVIRONMENT
• DATABASE ENVIRONMENT
• DESIGNING DATABASES
• DATABASE TRENDS
• MANAGEMENT REQUIREMENTS FOR DATABASE SYSTEMS

5
FILE ORGANIZATION

• BIT Binary Digit (0,1 Y,N On,Off)
• BYTE Combination of BITS which represent a
  CHARACTER
• FIELD Collection of BYTES which represent a
  DATUM or Fact
• RECORD Collection of FIELDS which reflect a
  TRANSACTION

6
FILE ORGANIZATION

• FILE A Collection of Similar RECORDS
• DATABASE An Organizations Electronic Library of
  FILES

7
FILE ORGANIZATION

• ENTITY Person, Place, Thing, Event about Which
  Data Must be Kept
• ATTRIBUTE Description of a Particular ENTITY
• KEY FIELD Field Used to Retrieve, Update, Sort
  RECORD

8
KEY FIELD

• Field in Each Record
• Uniquely Identifies THIS Record
• For RETRIEVAL
• UPDATING
• SORTING

9
SEQUENTIAL VS. DIRECTFILE ORGANIZATION

• SEQUENTIAL Tape Oriented One File Follows
  Another Follows Physical Sequence
• DIRECT Disk Oriented Can be Accessed Without
  Regard to Physical Sequence

10
FILING METHODS

• INDEXED SEQUENTIAL ACCESS METHOD (ISAM)
• EACH RECORD IDENTIFIED BY KEY
• GROUPED IN BLOCKS AND CYLINDERS
• KEYS IN INDEX
• VIRTUAL STORAGE ACCESS METHOD (VSAM)
• MEMORY DIVIDED INTO AREAS INTERVALS
• DYNAMIC FILE SPACE
• VSAM WIDELY USED FOR RELATIONAL DATABASES
• DIRECT FILE ACCESS METHOD

11
DIRECT FILE ACCESS METHOD

• EACH RECORD HAS KEY FIELD
• KEY FIELD FED INTO TRANSFORM ALGORITHM
• ALGORITHM GENERATES PHYSICAL STORAGE LOCATION OF
  RECORD (RECORD ADDRESS)

12
TRADITIONAL FILE ENVIRONMENT (FLAT FILE)

• DATA REDUNDANCY
• PROGRAM / DATA DEPENDENCY
• LACK OF FLEXIBILITY
• POOR SECURITY
• LACK OF DATA SHARING AVAILABILITY

13
DATABASE

• ORGANIZATIONS ELECTRONIC LIBRARY
• STORES MANAGES DATA
• IN A CONVENIENT FORM

14
DATABASE MANAGEMENT SYSTEM (DBMS)

• SOFTWARE TO CREATE MAINTAIN DATA
• ENABLES BUSINESS APPLICATIONS TO EXTRACT DATA
• INDEPENDENT OF SPECIFIC COMPUTER
  PROGRAMS

DBMS
15
COMPONENTS OF DBMS

• DATA DEFINITION LANGUAGE
• Defines data elements in database
• DATA MANIPULATION LANGUAGE
• Manipulates data for applications
• DATA DICTIONARY
• Formal definitions of all variables in database
  controls variety of database contents

DBMS
16
STRUCTURED QUERY LANGUAGE (SQL)

• EMERGING STANDARD
• DATA MANIPULATION LANGUAGE
• FOR RELATIONAL DATABASES

DBMS
17
TWO VIEWS OF DATA

• PHYSICAL VIEW Where is data physically?
• DRIVE, DISK, SURFACE, TRACK, SECTOR (BLOCK),
  RECORD
• TAPE, BLOCK, RECORD NUMBER (KEY)
• LOGICAL VIEW What data is needed by application?
• SUCCESSION OF FACTS NEEDED BY APPLICATION
• NAME, TYPE, LENGTH OF FIELD

DBMS
BIT BYTE FIELD RECORD FILE DAT
ABASE
18
RELATIONAL DATA MODEL

• DATA IN TABLE FORMAT
• RELATION TABLE
• TUPLE ROW (RECORD) IN TABLE
• FIELD COLUMN (ATTRIBUTE) IN TABLE

19
TYPES OR RELATIONS
20
HIERARCHICAL DATA MODEL
21
NETWORK DATA MODEL

• VARIATION OF HIERARCHICAL MODEL
• USEFUL FOR MANY-TO-MANY RELATIONSHIPS

22
OTHER SYSTEMS

• LEGACY SYSTEM older system
• OBJECT-ORIENTED DBMS stores data procedures as
  objects
• OBJECT-RELATIONAL DBMS hybrid

23
CREATING A DATABASE

• CONCEPTUAL DESIGN
• PHYSICAL DESIGN

24
CREATING A DATABASECONCEPTUAL DESIGN

• ABSTRACT MODEL, BUSINESS PERSPECTIVE
• HOW WILL DATA BE GROUPED?
• RELATIONSHIPS AMONG ELEMENTS
• ESTABLISH END-USER NEEDS

25
CREATING A DATABASEPHYSICAL DESIGN

• DETAILED MODEL BY DATABASE SPECIALISTS
• ENTITY-RELATIONSHIP DIAGRAM
• NORMALIZATION
• HARDWARE / SOFTWARE SPECIFIC

26
ENTITY- RELATIONSHIP DIAGRAM
27
NORMALIZATION

• PROCESS OF CREATING SMALL DATA STRUCTURES FROM
  COMPLEX GROUPS OF DATA
• EXAMPLES
• ACCOUNTS RECEIVABLE
• PERSONNEL RECORDS
• PAYROLL

28
DISTRIBUTED DATABASES

• PARTITIONED remote CPUs (connected to host) have
  files unique to that site, e.g., records on local
  customers
• DUPLICATE each remote CPU has copies of common
  files, e.g., layouts for standard reports
  and forms

29
DATABASE TRENDS

• MULTIDIMENSIONAL DATA ANALYSIS 3D (or higher)
  groupings to store complex data
• HYPERMEDIA Nodes contain text, graphics, sound,
  video, programs. organizes data as nodes.

30
DATABASE TRENDS

• DATA WAREHOUSE Organizations electronic library
  stores consolidated current historic data for
  management reporting analysis
• DATA MART Small data warehouse for special
  function, e.G., Focused marketing based on
  customer info

31
COMPONENTS OF DATA WAREHOUSE
32
DATABASE TRENDS

• ON-LINE ANALYTICAL PROCESSING (OLAP) ability to
  manipulate, analyze large volumes of data from
  multiple perspectives
• LINKING DATABASES TO THE WEB

33
ELEMENTS OF DATABASE ENVIRONMENT
34
DATABASE ADMINISTRATION

• DEFINES ORGANIZES DATABASE STRUCTURE AND
  CONTENT
• DEVELOPS SECURITY PROCEDURES
• DEVELOPS DATABASE DOCUMENTATION
• MAINTAINS DBMS

35
Connect to the INTERNET
Laudon/Laudon Web site http//www.prenhall.co
m/laudon Additional Internet Resources related
to this chapter http//www.oracle.com newscom
p.databases newscomp.databases.theory http//w
3.one.net/jhoffman/sqltut.htm http//www.compapp
.dcu.ie/databases/welcome.html http//www.acm.org
/sigmod http//www.dwinfocenter.org/ http//138.
87.1.4/DataWarehouse/whselead.html
36
CHAPTER 6. MANAGING DATA RESOURCES